A NCS (Networked Control System) is a feedback control system formed by a digital communication network and having control loops. It may be applied to technologies such as remote operation, industrial control, robot, and automated transportation tool control. However, the M2M network (or called Machine to Machine) that is currently developing rapidly provides a faster connection for a considerable number of sensors and actuators in the NCS, such that the NCS can be adapted to the Internet, not being limited to the traditional local area network any more.
However, in this case, the difficulty facing the traditional NCS control loops lies in how to handle the frequently occurring, highly mobilized, and dynamic network topological structure in the M2M network so as to overcome the constraints of the traditional NCS system.
In a hierarchical NCS, the local area controller is used for receiving sensor signals and sending simple commands; a higher-layer controller is connected to a plurality of NCSs via Internet or Ethernet and receives all information about connection to the NCS. It has a wider view angle on the logical layer and therefore may execute advanced businesses such as planning and scheduling, etc. However, such a structure has the following problems:
1. In the current NCS implementation, the connection between sensors, actuators, and control units is fixed, such that its mobile performance is relatively poor. However, in the wireless sensor and actuator network, a mobile device node may access or exit at any time; therefore, it is a dynamic network topological structure; the current NCS system cannot pre-configure or maintain a corresponding control loops.
2. The current NCS system basically does not have an error-allowance performance. If any means in the control loops, particularly a sensor or actuator, fails, it will directly damage the whole control loops.